Composite fluid-conducting tube



May 6, 1941. H. c. DANIELS COMPOSITE FLUID-CONDUCTING TUBE Filed Mal-cn s, 1939 2 Sheets-Sheet 1 fafa/a May 6, 1941- H. c. DANlEL I l 2,241,245

COMPOSITE FLUID-CONDUCTING TUBE Filed March 5, 1939 2 Sheets-Sheet 2 Patented May 6, 1941 2,241,245 COMPOSITE num-conocerme 'runs Harold C. Daniels, Woodbury, Conn., signor to Chase Brass Copper Co., Incorporated, Waterbury, Conn., a corporation Application March 3, 1939, Serial No. 259,570

(Cl. 13S-57) 3Claims.

This invention relates to improvements in fluidconducting tubes and more particularly to composite or multi-layer fluid-conducting tubes designed for the conveyance of liquids, gases. etc.,

where superior resistance to rupture is required.

One of the main objects of the present invention is to provide a superior composite fluid-conducting tube having superior reslstance to the crystallizing effects of mechanical vibration and hence longer life in use under severe conditions.

Another object of the presentv invention is to provide a superior composite fluid-conducting tubehaving superior resistance to bursting or leakage when subjected to the softening or weakening effects of high temperatures,l as. for instance during a conflagration.

A further object of the present invention is to provide a superior composite fluid-conducting tube combining superior resistance to bursting strains with capacity for being exed without kinking or rupture.

Still another object of the present invention is to provide a superior composite fluid-conducting tube providing a reserve duid-tight wall in the event of the rupture of the wall normally relied upon to confine the fluid being conducted.

With the above and other objects in view, as

-will appear to those skilled in the art from the present disclosure, this invention includes all features in the said disclosure which are novel over the prior art. l

In the accompanying drawings, in which certain modes of carrying out the present invention are shown for illustrative purposes:

Fig. 1 is a view in side elevation of one form of composite fluid-conducting tube embodying the i present invention;

Fig. 2 is a transverse sectional view taken on the line 2-2 of Fig. l;

Fig. 31s a view thereof in central longitudinal section;

4F'ig. 4 is a view partly in side elevation and partly in central longitudinal section of another The composite fluid-conducting tubes of the i present invention are admirably suited for employrnent in airplanes to conduct both fuel and :lubricating oil under circumstances where vibration is a factor which causes serious trouble by crystallizingy metallic tubing, thus causing its ultimate breakage and the attendant hazard of fire and mechanical damage to the power plant and the plane itself.

Thecomposite fluid-conducting tubes or ducts of the present invention are also useful in a wide variety of situations, but are specially well suited for use in refrigeration systems where high pressures are ordinarily employed and where the weakening of the inner tube in the event of fire would constitute a hazard to the fireman and otherwise.

The particular composite fluid-conducting tube herein chosen for illustration in Figs. 1 to 3 inclusive, comprises a body-tube I0 of relativelythin imperforate wrought-metal and preferably formed of copper, copper-base material, or other non-ferrous corrosion-resisting material well annealed to provide flexibility and superior resistance to crystallization. The major portion of the exterior surface of the said body-tube I0 is provided with a helical wrapping of sheet-metal vibration-dampening tape II. The sheet-metal tape II, as is especially well shown in Fig. 3, has its central portion I2 closely fitting the outer periphery of the body-tube Ill and has its respective opposite edge-portions I3 and Il deflected outwardly into concavo-convex form to such degree that the edge-portion Il of one convolution of the tape il will snugly t within and conform to the curvature of the opposite edgeportion I3 of the adjacent convolution of the said tape.

'I'he sheet-metal tape II is preferably formed of relatively-soft steel having the properties of superior tensile strength under elevated temperatures than would have the copper or similar nonferrous body-tube I0 when the entire structure is subjected to excessive heat as, for instance, in the event of the burning of the building in which it might be installed. The sheet-metal tape I I also is preferably formed of a material, such as steel, iron or bronze, which will have a different natural period of vibration from that of the bodytube Ill. so as to act as a vlbration-dampener therefor and thus retard the crystallizing effects of vibration upon the said body-tube III.

The terminal-end I5 of the body-tube ,Iii nts within a socket I6 in a terminal-fitting I1 and preferably abutsagainst a stop-shoulder I8 therein. as is shown in Fig. 3. 'I'he outer portion of the socket Il in the terminal-fitting l1 is shaped to provide a tapering convex deflectlngsurface I9 terminating at its portion of smaller diameter in the stop-shoulder Il and terminating at its opposite end in al threaded portion 20 in the inner portion of the said socket I3. The deiiecting-suriace I3 of the socket I3 in theterminal-fitting I1 is adapted to inwardly deflect the compression-lip 2I of `a clamping-bushing 22 which is sleeved over the terminal-portion I5 of the body-tube III and which is provided with an externally-threaded portion 22 engaging with the threaded portion 2li ofthe socket Il in the terminal-iltting I1. The portion of the clampingbushing 22 which projects beyond the back face of the terminal-fitting I1 is provided with a polygonal wrench-receiving head 24 by means oi' which the said clamping-bushing may be threaded tightly into the socket Il in the terminal-fitting I1 to a degree necessary to cause its clamping-lip 2I to .be deflected suiilciently against the outer periphery of the terminal-portion Iloi the body-tube I0, so as to form a fluid-tight joint with the said terminal-ntting and to firmly mechanically interlock the said body-tube therewith. The outer lace of the polygonal wrench-receiving head 24 of the clamping-bushing 22 is formed with an annular recess 25 into which extends the adjacent end of the sheet-metal vibration-dampening tape II which is preferably secured in the laid recess by means of a radial set-screw 23.

About midway of its length the terminal-iltting I1, which is preferably formed of brass or other non-ferrous material, is provided with a polygonal wrench-receiving portion 21 from which rearwardly projects an externally-threaded tubular stem 28- by means of which the iltting and hence the entire composite fluid-conducting tube may be attached to any desired piece of apparatus.

For the purpose oi illustration let it be assumed that the terminal-fitting I1 and hence the body-tube I0, vibration-dampening tape il and associated parts are connected to a refrigeration compressor. 'I'he vibration of the compressor will, of cousre, tend to crystallize the bodytube I0, but such crystallization will be very markedly reduced or nullied by the dampening action of the tape II which, by virtue of the fact that it is a discontinuous tube, will have a markedly-diilerent natural period of vibration from the natural period of vibration of the body-tube III and hence will dampen the vibrations of the latter and thus retard or prevent the crystallization of the same.

Now in the event of a ilre in the vicinity of the s tructure shown in Figs. 1 to 3 inclusive, the body-tube ,will soften at elevated temperatures and thus lose a large percentage of its tensile strength, with the result that the high pressure refrigerant within the body-tube I will expand the latter and ultimately burst the same, were it not for the fact that the reinforcing tape I I will still maintain a relatively-high tensile strength at the same temperature at which the body-tube I 0 materially weakens. Thus, in addition to acting as a vibration dampener, the tape II will act as an anti-bursting sheath for the body-tube I0 when the latter is so weakened by high temperatures as to no longer be able to effectively resist high internal pressures.

The character of the vibration-dampening it is preferable to interpose between the two said elements an insulating sheathing. which may be conveniently done by coating the body-tube III upon its exterior with an insulating varnish or lacquer or by winding the periphery thereof with l0 a tape of electrically insulating material.

I'he particular i'orm of the present invention illustrated in Figs. 4 to 6 inclusive, includesv an imperforate body-tube 30 formed of corrosionresisting wrought metal such as copper. etc.,

l5 and having its terminal-portion 3I entered into an axial socket 32 formed in one end of a terminal-iitting 33 and corresponding to the socket I6 before described and, like the same'. termi- ,nating at its outer end in a stop-shoulder 34,

2Q against which the adjacent end of the body-tube 3G abuts. Fitting into the socket 32 is a clamping-bushing 35 having the same general characteristics as the clamping-bushing 22 above described and, like the same, serving to form a fluid-tight connection between the body-tube 30 and the terminal-iitting 33 and also to provide a secure mechanical connection between the two said elements.

The terminal-fitting 33 is provided with an externally-threaded tubular stem 38 by means of which the assembly may be connected to the desired device such, for instance, as the compressor of a refrigerating system, the carburetor of an airplane engine or the oil reservoir thereof,

or the like. f

About midway of its length, the terminal-titting 33 is provided with a Wrench-receiving portion 31, and on the opposite side of the said wrench-receiving portion from the tubular stem 36, with an externally-threaded portion 38, as

described in connection with the structure shown in Figs. 1 to 3 inclusive and, like the same, having its convolutions interlocked against separation along the axis of the structure.

Wrapped around the vibration-dampening tape 39, so as to lie in the valleys or grooves formed by the shaping and intertting of the various convolutions of the said tape, is a helically-arranged resilient spacing-cord 40, which in the structure shown is in contact with the inner surface of a guard-tube 4I axially positioned with respect to the body-tube 30, vibration-dampening tape 39 and the resilient spacing-cord 40. The spacing-cord 40 is preferably formed' of synthetic rubber or other non-metallic vibration-dampening material capableof resisting the softening or disintegrating action of oil, gasoline, Arei'rigerating iluids, etc., though the said spacing-cord may, ii' desired, be formed of such material as asbestos, textile material, or

the like.

The terminal-portion 42 of the guard-tube 4| fits within the inner end-portion 43 oi' a coupling-tltting 44, which is provided with an internally-threaded outer end-portion 45`threadedly tape II is such that as the body-tube I0 is bent Z0 receiving the externally-threaded portion 38 of to meet the'exigencies of different installations. l

the said anti-vibration tape II will freely flex with the body-tube I0 without opening up any of the joints between the convolutions of the said tape.

the terminal-fitting 33 before described.

As thus constructed and arranged, the intermediate portion of the coupling-tting 44 provides an interior chamber 48, the outer end-wall of which is formed by the terminal-ltting 33 and the clamping-bushing 3i and which is in communication with the interior of the guard-tube 4 I, as shown in the drawings.

The interior of the inner end-portion 48 of the coupling-fitting 44 is provided with a tapering deflecting-surface 41 which merges into internal threads 4I within said inner end-portion 43 of the coupiing-ntting 44. Sleeved over the `terminal-portion 42 of the .guard-tube 4i is a clamping-bushing 40 having external threads Il on its intermediate portion which engage with the threads 4lof the coupling-dtting 44, as is shown. The saidclamping-bushing is also provided with a compression-lip Ii' engageable with the deilecting-s'urface 41 in the coupling-fitting 44, tofbe thereby pressed into intimate `engage- 4Q of the connecting-fitting 44 -than prevails inA the body-tube lvl, a fracture in the latter will permit thev leakage of the higher pressure. outside or the said body-tube into the same and time` cause the gauge connected to the pipe I4 to in.:`

d icate a drop in pressure. In either event. by"

' means of a suitable gauge. the operator may be meniwltn the periphery of the terminalpartum 42 of the guard-tube 4I to insure a fluid-tight connection and fa substantial mechanical connection between the said guard-tube and the said coupling-fitting. The end of the clamping-bushing 4l opposite ,its compression-lip Il is provided with a wrench-receiving portion l! by means ofl which it may be threaded firmly vinto place. Preferably the coupling-fitting 44 is formed in its periphery about midway of its length with a lateral port Il which is internally threaded and dent to the service referred to willtend to vibrate. the said body-tube and therefore tend to crystallize the same. but the vibration-dampening tape 39 having as it does a different natural period of vibration from that of the said bodytube, will effectively minimize such tendency to crystallize. Furthermore. the resilient spacingcord -40 will also serve to absorb and dampen the vibratory energy not only of the body-tube but also of theguard-tube 4l. 'Ihe construction being such that the body-tube 30, vibrationdampening tape Il, and the guard-tube 4I may be bent, as required by circumstances. without depriving the assembly of the vibration-dampening properties 'and without parting the interlocked convolutions of the said tape.

Now let it be assumed that for som-e reason a rupture actually occurs in the body-tube III 'so that pressure from within said body-tube 3h will eiIect or be effected by the predetermined pressure (air-pressure, for instance) maintained in the chamber 46 of the coupling-fitting 44. The resulting pressure vchange will be indicated by a suitable pressure-gauge connected to the pipe 54, thus warning the operator that a fracture has occurred in the Vbody-tube 3l.

It'may be explained in this connection that in the event of a' fracture of the body-tube '30 in that portion of its length which is covered by the anti-vibration tape 39, the iluid may escape into the chamber 4.6 in the coupling-fitting 44 by way of the helical passage formed between the crowned portions of the said tape l! and the outer-periphery of the body-tube 30. It may also be explained in this connection that if the pres-'- sure (air-pressure for instance) in the chamber 44 of the connecting-tting 44 is maintained at -w'arned of any rupture inthe body-tube Il; In theevent of a rupture such as those above referred to in the body-tube 3l, the guard-tube will still maintain a fluid-tight duct, and after the same has become filled withthe fluid being 'onveyed, the supply of fluid will continue .to i'iow through the body-tube Il without causing an interruption -of service or re vhazard orthe like until such time as repairs o r replacements caribe made.

The invention may be carried out in other specinc ways than those herein set forth without departing from the spirit and essential characteristics of the invention. and the present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, and all changescoming within the meaning and equival'ency. range of the appended claims are intended to be embraced therein.

f;- I claim:

i. l. A composite huid-conducting tube-structure, including inA combination: an imperforate wrought-metal body-tube having substantiallysmooth interior and exterior surfaces; a wroughtmetal guard-tube substantially concentrically ar.

` rangedl with respect vto the said body-tube and surrounding the same: and a vibration-dampening ribbon or tape of reinforcing metal having its lcbnvolutions mutually interlocked and helically extending around the exterior of the said -bodytlibe and located within the interior of the said guard-tube. and having a natural period 4of vibration differing from the natural period of vibration of both the said body-tube and the said guard-tube.

2. A composite fluid-conducting tube-structure, including in combination: an imperforate wrought-metal body-tube having substantiallysmooth interior and exterior surfaces; a wrought-metal guard-tube ntted over the said body-tube: a vibration-dampening tape helically wrapped around the exterior of the said bodytube and having its convolutions mutually interlocked in a manner providing a helical groove omits exterior surface; and a spacing-cord helically wrapped around the exterior surface of the s ai'd helically-wrapped vibration-dampening tape o rijribbon in the helical groove therein and extending into close proximity to the interior surface of the said guard-tube to guard the same and the said body-tube against crystallization inci ent to vibration.

,a A composite fluid-conducting tube including infj'ncombination: an imperforate wrought-metal body-tube; and a vibration-dampening ribbon or tapey ofl reinforcing metal helically-wrapped about the exterior of said body-tube; each helical convolution between two adjacent convolutions having a ,helical central portion of substantial width supporting and reinforcing the said bodytube and also having helical opposite edge-portions extending from said central portion: both ot said edge-portions being of similar concave- 'convex form and with the concavity of each directed toward said body-tube; each two adjacent concavo-convex edge-portions of adjacent convolutions being arranged in overlapping sliding relation; and the' said ribbon or tape having a markedly-different natural period of vibration than 4the said body-tube to guard the latter against crystallization.

HAROLD C. DANIELE. 

